A SUBMILLIMETER SURVEY OF W49A - SUPPORT FOR THE CLOUD-CLOUD COLLISION MODEL OF W49N

Results are presented of a JCMT continuum mapping study of the massive star-forming region W49A at 450, 800 and 1100 mu m. The three known f ar-infrared components of the source, W49N, W49SE and W49SW, are obser ved at all wavebands. The flux densities, temperatures, luminosities a nd gas masses of the three sources are derived. In addition, a new sou rce is detected at 450 mu m, 80 arcsec east of W49N, which is here lab elled W49NE, It is seen that W49N is significantly more massive than t he other sources, and is the only one to contain an extended, cold dus t component. In the highest resolution dataset, taken at 450 mu m, it can be seen that the peak of the source W49N is at least double, with a suggestion of a third component. This is consistent with recently pu blished (CS)-S-34 data, which appear to show that the cluster of H II regions seen in W49N is the result of star formation triggered by a cl oud-cloud collision. The agreement between our data and the (CS)-S-34 data, in terms of both morphology and relative masses, leads us to sup port this hypothesis.